In co-pending application Ser. No. 107,933 I disclosed an improved gear box assembly for a vertical axis wind turbine, the vertical axis wind turbine having a rotor having a centrally disposed axis oriented in the vertical direction, a bull gear supporting the rotor, a base below the bull gear, the bull gear and base presenting a hollow housing and shaft terminating in an inner end wall and end surface respectively, the housing for receiving the shaft, one of said hollow housing or shaft being stationary and the other being rotatable with respect thereto and secured to the bull gear, the shaft and housing when secured together presenting a space between the inner end wall and end surface, bearings supported between the housing and shaft, a fluid passageway extending into the space created between the inner end wall and end surface for feeding hydraulic fluid under pressure into the space for hydraulically elevating the bull gear relative to the base, means precluding the gear from rising more than a predetermined distance or controlled distance, means for feeding the fluid under pressure to, and means draining the fluid from, the space, and reservoir for such fluid.
While the aforesaid structure overcomes problems discussed in the said application, I have discovered a more efficient approach to hydraulically supporting the bull gear, rotor and/or guy wires of vertical axis wind turbines and particularly the bull gear, rotors and guy wires. Particularly, in the description of the embodiment of the invention disclosed in the aforesaid patent application, the rotor is wholly supported by the bull gear. Therefore, when the bull gear is hydraulically lifted and supported, the rotor is also lifted. In the larger wind turbines (for example, wind turbines that generate greater than 1/3 megawatt) and forces exerted between the end of the rotor and seat, and resultant wear and tear of the metal between the rotor and seat, increase dramatically thereby increasing the intervals between maintenance and decreasing the useful life expectancy of the wind turbine.
Additionally, when the rotor of the vertical axis wind turbine is braked as described in the said co-pending application, the guy tensioning ability of the wind turbine ceases.
In the said co-pending application, I also disclosed an emergency safety device for assisting to brake the wind turbine when the angular velocity of the rotor exceeded a predetermined velocity. In this regard, the opening of a normally closed valve leading from the space between the bull gear and shaft (over which the bull gear rotated when elevated by the hydraulic fluid) occurred when the weighted pendulum that rotated with the rotor reached a predetermined extended position-when the angular velocity of the rotor exceeded a predetermined angular velocity. While this approach was an improvement to prior art approaches, its reliability to open at a predetermined angular velocity could not be assured because of for example, friction.
It is therefore an object of this invention, to provide an improved vertical axis wind turbine and components therefor, including hydraulic suspension systems, braking system, and an overspeed safety device wholly reliable in emergency situations, and components therefor, which overcome the aforementioned deficiencies found in prior art structures. These improvements also include an improved hydraulic suspension system for hydraulically supporting the rotor shaft, bull gear and rotor shaft together and in some embodiments maintain the tension of the guy wires of the vertical axis wind turbines even when the bull gear has been braked, and more efficient components for these structures, and a reliable overspeed safety device which operates in emergency situations to effectively shut-down the operation of the vertical axis wind turbine.
Further and other objects of the invention will be realized by those skilled in the art from the following summary of the invention and detailed description of the preferred embodiments thereof.